Mailing List flyrotary@lancaironline.net Message #5177
From: Michael Joyce <MikeJ@B9Creations.com>
Subject: Re: [FlyRotary] Re: evap core air pockets?
Date: Wed, 07 Jan 2004 20:58:08 -0700
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Thank for the informative responses!
Best!
MikeJ

Russell Duffy wrote:
Message
Excuse my extreme rotary newness, but what are "parallel cores"?
Thanks,
MikeJ 
 
Consider yourself excused :-) 
 
Lots of folks use AC evaporator cores for radiators, and it typically requires two of them to cool a 13B engine.  The plumbing options are "series", where you flow from the engine into one of the cores, then out of that one, into the 2nd one, then out and back to the engine.   "Parallel" would be where you come out of the engine, then use a Y or a T to flow to both cores at the same time.  On the outlet of the cores, you Y or T them again, and go back to the engine.   
 
The Parallel method offers less resistance, thus a theoretically higher flow rate.  It also puts the hottest coolant in contact with more cool air than you would in series.  This should clearly be the preferred method.  The downside is the extra connections that are required, and the fact that sometimes it's hard to make the water flow evenly between the cores.  For example, if you need a few more turns, length of hose to get to one of the cores, the other one will probably flow more coolant.  In and extreme case, hardly any coolant will pass through the more restrictive core.  Series makes sure that both get even flow, and simplifies the plumbing.  
 
Cheers,
Rusty

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